Blog

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Creating scale models of precast concrete tanks with 3D printed moulds

Ronan Walsh

Introduction and requirements

Usually, a specific wastewater project will require multiple of the same, or different tank sizes, to be connected in an array. We produce more than twenty individual tank types (the most comprehensive range in Ireland), in sizes from 850 litres to 38,000 litres (the largest two-piece tank in the country).

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Lately we looked at options, to see if there was a way we could produce miniature scale models of our precast concrete tanks for demonstration purposes at customer offices or trade exhibitions. This would be in addition to detailed computer-aided design illustrations and models, arranging visits to our production facilities, and in-person project site visits.

For these miniature scale models to be a helpful aid in demonstrating our precast concrete tanks to our customers, we set out the following requirements:

  • Materials used to give a realistic impression of an actual precast concrete tank

  • Scaled to a size to ensure that: important details of the tanks are represented, amount of space required in an office to show the models is minimal, and each tank model is set at the same scale to allow for side by side comparisons

  • Additional miniature models of the precast concrete tanks can be reproduced as required

Process

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After some research and procurement of materials, the process below was followed:

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GAA Sponsorship Announced

Molloy Precast

Molloy Environmental Systems, Clara Road, Tullamore now sponsor the Offaly Club Hurling Championship. Speaking at the official launch at O’Connor Park, Tullamore on Tuesday 26th of February, Donal Molloy, managing director said: “We are delighted to be able to sponsor such a prestigious tournament. We see it as the joining of two forces that have much in common; a desire to excel and to show best practice.”

“It is important for businesses to invest locally. I firmly believe as do my team that Offaly is a great county and we as a company should support where and when we can, local organisations that reach out and unite local communities.” continued Mr. Molloy.

The sponsorship extends to the Senior, Intermediate, Junior ‘A’, Junior ‘B’ and Under-21 Hurling Championships.

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Percolation installation and sizing

Molloy Precast

How does a percolation area work?

A percolation system is now standard for all new septic tanks installed in Ireland today. These systems are engineered to treat the partially treated effluent from the septic tank and to distribute this treated liquid into the underlying ground water. If constructed correctly, and the site has the right conditions a standard percolation system will last trouble free for many years with little maintenance. A typical percolation system is composed of a series of trenches half a meter wide and 18m long. Each trench is made up of the following components as seen in the image below, 250mm of clean stone, a 4” distribution pipe, a second layer of clean stone to cover the pipe and a geotextile membrane covered with a layer of soil brought up to ground level. It is important that the trench is ventilated for an adequate oxygen supply.

Percolation cross section

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Domestic Wastewater Treatment

Molloy Precast

Over 400,000 households in Ireland have on-site wastewater treatment systems. Typical wastewater treatment systems have two components, namely, a septic tank and a percolation area. Both components are essential to ensure adequate wastewater treatment. Inadequately treated wastewater can impact on the quality of ground water, drinking water and surface water which in turn can affect human health as well as the surrounding environment.

Domestic wastewater is made up of solids, biological pollutants as well as fats, oils and greases (FOGs). Removal of these materials is by a combined effort between the septic tank and percolation system. The purpose of a septic tank is to remove FOGs and solids from the wastewater, while the purpose of the percolation area is to biologically treat the wastewater, removing biological pollutants and to distribute treated wastewater into the groundwater network.

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Septic Tank Problems

Molloy Precast

If you are having difficulties with your Septic Tank, the decision tree below helps find the issue with your septic tank, and points you towards possible solutions.

Septic tank problem

Troubleshooting problems with the on-site wastewater treatment system

Problems with septic tanks are generally noticed when toilets and other household utilities stop functioning properly or if the septic tank begins to overflow. The first thing to check when this happens is if the pipes leading to the septic tank are blocked. If the water levels in the septic tank are normal, then there is a blocked or collapsed pipe somewhere. If this is not the case there is either something wrong with the septic tank or the percolation system.

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Site Assessors in Ireland

Molloy Precast

Home Builders: Molloy Precast can provide you with a Site Suitability Report; however, this report is based on a site characterisation report completed by a competent and qualified person i.e. a site assessor. This page provides you with a list of names and contact details county by county of site assessors.

Site Assessors: To be included in this list, free of charge, please phone John Brennan on 057 93 26000 or email john.brennan@molloyprecast.com.

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New Septic Tank device from Molloy Precast

Molloy Precast

Molloy Precast will be bringing to market a percolation distribution device that has the potential to solve common problems associated with septic tank percolation areas. In the presence of Phil Hogan, Minister for the Environment on his recent visit, Molloy Precast signed a licence agreement with Trinity College Dublin who have designed and patented the device.

Typically in rural domestic houses, sewage is treated on site by a septic tank. Sewage then flows by gravity into a percolation area where it is further treated to a quality suitable for discharge. A TCD research team headed by Dr. Laurence Gill, has shown that the current means of gravity discharge to percolation areas fail to work consistently under sporadic and very low flows typical of septic tank effluent. In the percolation area, it is crucial that effluent is distributed evenly between the trenches to ensure effective treatment. A device to ensure an effective distribution between each trench, and along each trench without any electrical input has been designed and patented by this TCD research team.

Molloy Precast are working to commercialise this device and will bring it to market in the near future. Commenting on this new innovation, Donal Molloy of Molloy Precast said “We are delighted to be linked with Trinity College Dublin and Enterprise Ireland in bringing this device to market, once available in Ireland, we believe this product will have export potential.”

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Environment Minister opens Molloy percolation demonstration facility

Molloy Precast

Phil Hogan T.D. Minister for the Environment, Community and Local Government described Molloy Precast’s facility as “fantastic and hugely educational” during his official visit on Thursday June 7th. He was there to officially open the company’s purposely built percolation demonstration and rainwater harvesting facility at Clara Road, Tullamore, Co. Offaly. The weather which greeted the minister on the day was quite apt with water, water everywhere.

The facility which is Ireland’s only percolation demonstration facility features every percolation system available on the Irish market and is entirely focused on ensuring the education of best practice in percolation design and installation to homeowners, construction professionals and students. In simple terms the facility demonstrates how different percolation systems function, how they should be correctly installed and the EPA’s guidelines for the design and sizing of each system. In addition, the site also features a fully operating rainwater harvesting system.

Furthermore, in association with Trinity College Dublin and Enterprise Ireland, Molloy Precast will be bringing to market in the coming months a percolation distribution device patented by Trinity College that has the potential to solve many of the common septic tank problems in the country. The formal signing of this most recent innovation was completed in the presence of Minister Hogan during his official visit.

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PhD student funded to research at NUI Galway

Molloy Precast

Molloy Precast are funding a PhD student, Shane Fox from NUI Galway, to carry out research on optimising small scale wastewater treatment systems.

Small wastewater treatment plants can be susceptible to infrequent supervision, increased energy costs, shock wastewater loads, while simultaneously required to meet stringent wastewater discharge limits. This study examines the potential of real time control of wastewater treatment systems that will allow desired effluent standards to be met while simultaneously improving energy efficiency. A pilot test centre was constructed develop and test a robust intelligent treatment control programme that monitors influent concentrations, and subsequently adjusts the treatment cycle to improve energy efficiency as well as significantly reducing breaches of discharge limits.